Improvement in manufacture of molders  match-plates



CHARLES TRUESDALE AND ABNER J. SENNETT, OF CINCINNATI, OHIO.

IMPROVEMENT IN MANUFACTURE OF lVlOLDEBS MATCH-PLATES.

Specification forming part of Letters Patent No. 5 El,346, datedDecember 5', 1865.

To all lwhom it may concern:

Be it known that wia-CHARLES TRUESDALE and ABNER J. SENNETT, ofCincinnati, Hamilton county, Ohio, have invented a new and Improvedlrocess for the Manufacture of Patterns and Match-Plates; and we dohereby dc- Clare the following to be a full, clear, and exactdescription thereof, reference being had to the accompanying drawings,making part ot' this specification.

Our invention relates to a mode of obtaining the reverse side frompattern-blocks for ornamental castings or relieves, stove-designs,patterns, 85e.

Figuresl to 7, inclusive, represent successive stages of our process.

Upon a pattern-block, A, having the customary guide eyes or plates, weplace a drag, B, and pour over the block A sufficient plaster-of-paristo form a preliminary matrix, and ram in behind with sand. (See Fig. 1.)\/Ve then turn the drag and pattern -block, withdraw the block from theplaster cast, put the cope C on the drag, lill the cope withmolding-sand, and compress the sand iu the usual way. (See Fig. 2.) Wethen lift or separate the cope C from the drag B, destroy thepreliminary matrix, and return the drag B to the pattern-block A, andagain lill thedragB, but this time wholly with molding-sand. (SeeFig.3.)Wethen turn the drag and pattern-block and withdraw the blockfrom thedrag. We then reverse the drag and place upon it an open wooden frame,D, having suitable eyes to tit the pins of the drag, and a gate,d,forthe reception ofa mastic com posed of two parts of mineral pitch,one part of pnlverized soapstone or brick-dust, and one part of sawdustor other suitable molding composition, which is then poured in, theentire flask being set at a suitable cant to insure the entrance of thecomposition without washing away the face ofthe mold. (See Fig. 4.) Thecomposition cast, having sufficiently cooled, is then withdrawn, frameand all, from thelask, and its obverse surface D is coated with wax, ora mixture of paint and sand or other suitable substance, to acorresponding thickness with that desired for the ultimate cast orpattern. (See Fig. 5.)

The cast E thus obtained is a permanent and durable fac-simile of theblock A, the delicate outlines of which, being usually workedin putty orwax, are very fragile and easily injured.

By the process described the most delicate outlines are preserved in adurableI form, and not liable to injury by workmen.

The blocliA can be preserved or worked over for other purposes.

A complete composition castmay `now be obtained by taking a sand moldol' Fig. 5, as at Fig. G, and replacing the plate D E with an emptyframe, F, and running com position therein. (Sec Fig. 7.) We have then apermanent and exclusively composition eastot' both surfaces oftheobject, which cast may be used for-f4 any length of ti me in the Ordinary way of using match-plates.

To obtain either castings or metallic patterns from the compositioncasts made in the manner described above, they are molded in the usualway that sin gle and double faced matchplates are.

rEhe usual way of obtaining a reverse side from a pattern-block is totake the block and inclose it with a frame with the customary pins andguide-eyes and take a cast therefromA in plaster, then remove the castand put a thickness on the plaster with wax or with a composition ofpaint and sand. A reverse obtained in this way is subject to thefollowing among other disadvantages:

First, when the cast is taken the wood absorbs a portion ofthe moisturefrom the plaster and expands before the plaster sets, and when dry thewood contracts. Thus the frame becomes lower than the plaster cast, andto a certain extent loose therefrom, thereby rendering it impossible toobtain a perfect castiu g. It can only be used with success before thewood contracts.

Second, a reverse obtained in this way isliable to absorb moisture fromthe atmosphere and natural dampness of foundries, which causes it toeasily crumble.

Third, the waste of material. Owing to the causes stated above, newreverse sides to pattern-blocks, such as desirable designs forstovepatterns, have to be frequently taken, and each cast so take-n musthave athickness put on the reverse, the old material being thrown out asrefuse.

The following are among the many advantages of a composition cast madein the manner described:

First, it will not change from the effects of atmosphericheat or coldland is impervious to moisture.

Second, it is easily prepared for use. If

the thickness.

properly made, is ready for the molder after being cast,Withenoy otherlabor thaneputtingon (See Fig. 5.)

Third, an original being cast and the thickness put on, it can be copiedor duplicated to any extent desirable, andvis ready for use after beingcast, With no' other labor.

Fourth, the composition tenacionsly adheres to Wood, never liable-,tobecomeloose, and. if by accident the casts should beinjured the material can be remelted and used again.

Onr process may be slightly modified by applying the thickness of wax orpaint and sand to the plaster matrix, (see Fig. 1,) so as to dispensewithvthe operations shown in Figs. 5, 6,

